Concentration of minerals



Patented Sept. 14, 1954 CONCENTRATIQN F MINERALS Arthur H. Fischer, New York, N. Y., assignor to Minerec Corporation, New York, N. Y.,. a corporation of New York No Drawing. Application December 2, 1950,

Serial No. 198,897

11 Claims. 1

This invention relates to the concentration of minerals contained in. mineral-bearing materials such, for example, as ores and has for an object' the provision of an improved process for concentrating minerals. More particularly, the invention contemplates the provision of an improved process for concentrating minerals by froth flotation. A specific object of the invention is to provide an improved process for concentrating sulphide minerals by froth flotation. Further specific objects of the invention are to provide improved processes for concentrating copper sulphide minerals, zinc sulphide minerals and. lead sulphide minerals by froth flotation. Another object of the invention is to provide novel and effective flotation reagents. A further object of the invention is to provide new products, particularly, improved flotation reagents.

The invention is based. on my discovery that a flotation froth containing a mineral collecting agent. produced in an operation employing normal frothing and conditioning agents as well as the mineral collecting agent, responds to the incorporation of a plasticizer therein in many respects as organic plastic materials respond to the incorporation of the same plasticizers therein, being modified by the actions or functions of the plasticizers to form resilient, flexible and Workable froths when employed even in rather minute quantities in operations that would result in the production of brittle and unstable froths under otherwise identical conditions, even though the plasticizers themselves have no flotative capacities or properties or have only relatively insigniflcant flotative capacities or properties.

The plasticizers appear to possess the ability to create or have the property of creating a new flotative environment in which the flotation reagents employed become endowed with increased flotat-ive powers or capacities or properties either because of improvements in one or more of the other reagents resulting from the presence of the plasticizer or because, in the flotative environment, the plasticizer itself is so influenced by the other reagents as to acquire substantial flotative qualities of an additive character.

The plasticizer accelerates distribution in flotation pulps of water-insoluble mineral collecting agents with the result that the production on the mineral particles to be recovered of films comprising the mineral collecting agent is accelerated.

The results of my researches and investigations indicate that the acceleration of distribution of the water-insoluble mineral. collecting agent results from plasticization of the mineral collecting agent and that the improvements in the flotative properties of mineral collecting agents], both water-insoluble and water-soluble, results from. incorporation therein of the plasticizers with resulting plasticization.

The plasticizers and the mineral collecting agents may be mixed together prior to their introduction into the flotation 'pu-lps, or the plasti- 'cizers and the mineral collecting agents. may be introduced into the flotation pulps separately- Water-insoluble mineral collecting agents and plasticizers may be mixed together prior to their introduction into the flotation pulps or they may be introduced into the flotation pulps separately with about equal advantage. Water-soluble mineral collecting agents and plasticizers preferably are introduced into the flotation pulps without preliminary mixing. Mixing of the plasticizers. and the water-insoluble mineral collecting agents may be carried out under any suitable temperature and pressure conditions. Normally, mixing of the plasticizers and the. mineral col-lecting agents may be carried out at ordinary room temperatures and pressures prevailing in the plants in which mixing is carried out Incorporation of a plasticizer and a mineral collecting agent in a flotation pulp, whether mixed beforehand oradded to the. flotation pulp separately, results in the formation on particles of mineral to be recovered of films of plasticized mineral collecting agent comprising both the mineral collecting agent and the plasticizer.

When mixing-0f the plasticizer and the waterinsoluble mineral collecting agent is carried out prior to introduction into the flotation pulp, a plasticized mineral collecting agent is produced, and the plasticized mineral collecting agent is introduced into the flotation pulp.

When a plasticizer and a mineral collecting agent are introduced into the pulp separately, plasticization of the mineral collecting agent may be effected largely while the mineral collectin agent is dispersed in the liquid portion of the pulp, or largely after the mineral collecting agent has formed films on the mineral particles.

When a water-insoluble mineral collecting agent is employed, the time or place of plasticizetion depends upon the time or order of incorporation in the pulp of the mineral collecting agent and the plasticizer. If the'water-insoluble mineral collecting agent and the plasticizer are m corpcrated in the pulp separately, but substantially simultaneously, plasticization of the mineral collecting agent may be effected largely or pulp. When the plasticizer is incorporated in the pulp before or after incorporation of the waterinsoluble mineral collecting agent, the degree or amount of plasticization effected in the liquid portion of the pulp may be greater or less than the degree or amount of plasticization effected when they are incorporated separately but substantially simultaneously; When a water-soluble mineral collecting agent is employed in conjunction with a plasticizer,.plasticization may take place largely or substantially entirely after the mineral collecting agent has formed films on the surfaces of the mineral particles regardless of the time or order of incorporation in the flotation pulps.

, Plasticization of the mineral collecting agent takes place substantially immediately, with substantially immediate improvement in the flotative properties of the mineral collecting agents and, in the case of water-insoluble mineral collecting agents, with substantially immediate improvement in the rates and degrees of distribution of the mineral collecting agents. A particular advantage of the invention resides in the fact that the use of a plasticizer results in distribution of the mineral collecting agent throughout the flotation pulp in a relatively short period of time, as, for example, in less than a half minute when the pu p with added mineral collecting agent and plasticizer is properly agitated. The plasticizer improves the capacity of the mineral collecting agent to coat the mineral particles and rapid distribution of the plasticized mineral collecting agent throughout the pulp provides for multiplication of the opportunities for the mineral collecting agent to contact and form films on the mineral particles with a consequent reduction in the time required for conditioning the pulp prior to initiation of frothing operation proper.

In a froth fiotationoperation, a conditioning agent such as an alkaline substance or an acid substance, a mineral collecting agent and a frothing agent usually are incorporated in an aqueous pulp of the ore, and the pulp subsequently is subjected to aeration and agitation to produce a froth containing the valuable mineral of the ore. Usually, at least a brief period of time may be required to condition the pulp, as by agitation, after incorporation of the conditioning agent and the mineral collecting agent to effect thorough distribution of the conditioning agent and the mineral collecting agent throughout the pulp prior to the incorporation of the frothing agent in the pulp. When a water-insoluble mineral collecting agent is employed, in the absence of a plasticizer, a relatively long conditioning period, for example, a half hour to an hour or longer, may be required to effect distribution of the mineral collecting agent to the extent that a substantial recovery of valuable minerals may be effected.

When a water-insoluble mineral collecting agent is employed in accordance with heretofore customary practices, the amount or percentage of valuabl mineral recovered in the flotation operation is a function of the time of conditioning to effect distribution of the mineral collecting agent and filming of the mineral particles. If preliminary conditioning prior to flotation is not provided for, or, if a relatively short period of conditioning is provided for, recovery of valuable minerals may be so low as to make the operation unprofitable or uncommercial.

cussions contained herein.

In flotation operations conducted heretofore, the amount of recovery, or the percentage recovery, of valuable mineral is a function of the amount of mineral collecting agent that forms films on the mineral particles, and, to some extent, the amount of mineral collecting agent that forms films is a function of both the amount of mineral collecting agent added to the pulp and the time of conditioning the pulp containing the added mineral collecting agent. If the conditioning period is not suificiently long, only a portion 'of the mineral collecting agent functions to form films on th mineral particles even when an amount of mineral collecting agent sufficient to form proper films on all of the mineral particles is employed. Consequently, the amount of mineral collecting agent that can be employed effectively is restricted and recoveries are relatively poor. Also, the use of excess water-insoluble mineral collecting agent, that is, mineral collecting agent that does not form films on the mineral particles, results in the production of a poor froth in the subsequent frothing operation which further limits the recovery of valuable mineral.

The present invention permits th incorporation in the pulp and the effective use of an amount of mineral collecting agent sufficient to form proper films on all mineral particles.

, A further important advantage of the invention results from the fact that rapid distribution of a Water-insoluble mineral collecting agent is effected with consequent shortening or elimination of the conditioning period. For example, in a mineral recovery or concentration plant in which a conditioning period of a half hour orv an hour is required to produce a suitable recovery and in which the time of flow of the pulp through the frothing operation is about fifteen minutes, conditioning facilities must be provided for handling two or four times the amount of I pulp actually subjected to the frothing operation or mineral recovery operation proper, with attendant increased costs of installation, maintenance and operation. When, in accordance with the present invention, the time required for conditioning is reduced to a half minute or less, conditioning equipment can be substantiallycompletely dispensed with, and the conditioning and mineral collecting agents can be added to the pulp in a small compartment immediately ahead of the first frothing compartment. This advantageous result of the invention permits the immedate use in plants not equipped with conditioning equipment of highly efficacious waterinsoluble mineral collecting agents that otherwise cannot be employed effectively. a

It is to be understood that the scope of the invention is not .to be limited by theoretical dis- Whatever the explanation may be, it is a demonstrable fact that the incorporation in a flotation pulp to which is added a mineral collecting agent and the normal frothing and conditioning agents of a plasticizer normally effective for plasticizing organic plastics in amounts even as small as five one-thousandths (0.005) of a pound per ton of are treated may result in the production of profound improvements in the flotation operation and in the metallurgy of the mineral or metal recovery operation of which the flotation operation is a part. The addition of the plasticizer (1) Produces a resilient, flexible andworkable froth in a flotation operation that would produce a brittle and unstable'froth under other wise identical conditions,

(2) Permits the application of more mineral col-.- lecting agent for increased collecting power without detriment to the froth,

(3) Reduces the time necessary for conditioning the pulp with mineral collecting agent,

(4) Increases the speed of the flotation operation, and

(5) Yields generally improved metallurgical results.

The intimate relationship of dispersed and dispersing phases involved in the plasticizer effect is felt not only in the conditioning process but, also, in the process of froth formation and results in an over-all improvement in the mechanics of the operation.

The plasticizer preferably is employed in amounts in the range 0.01 to 0.005 pound per ton of ore treated, but it may be employed in greater or lesser amounts when conditions warrant such modification.

Among the commonly known plasticizers that I have found to be highly effective in flotation operations are included esters of phthalic acid, sebacic acid, citric acid, tartaric acid, phosphoric acid, succinic acid and hydroxybenzoic acid such as salicylic acid, such, for example, as

Diethyl phthalate Dibutyl phthalate Dihexyl phthalate Dibutyl sebacate Dihexyl sebacate Tributyl citrate Triamyl citrate Dibutyl tartrate Diamyl tartrate Tri-cresyl phosphate Amyl salicylate Diamyl succinate Diethyl adipate Dibutyl adipate Dihexyl adipate While the plasticizers may be employed with advantage in conjunction with all mineral collecting agents, including both water-soluble and water-insoluble mineral collecting agents, employed in flotation practice with the normal frothing and conditioning agents, my researches and investigations indicate that plasticizers are most effective and better results are obtained when they are employed in conjunction with the water-insoluble alkyl xanthogen formates, both symmetrical and unsymmetrical. Other specific mineral collecting agents with which plasticizers may be employed advantageously include, for example, alkali metal xanthates and dialkyl 1dithiophosphates. Representative xanthogen formate compounds suitable for use as mineral 1collecting agents include Ethyl xanthogen ethyl formate Butyl xanthogen ethyl formate Amyl xanthogen ethyl formate Hexyl xanthogen ethyl formate The claims of this application are directed to methods or processes employing esters of phthalic I acid. Methods or processes mploying plasticizers in the forms of esters of others of the acids referred to herein are covered by my copending applications Serial No. 198,896, filed December 2,

Example I Test N0 1 2 Heads, percent Cu 4.73 4. 746 Concentrates, percent Cu... 21. 62 22. Tails, percent Cu .236 210 Reagents Lime pounds per torn. 10. 0 l0. 0 Pine oil -4 .do.. 12 12 Hexyl xanthogen ethyl formats" do .045 Dibutyl phthalate -.d0 005 Example II Test Now... l I 2 Heads, percent 011..." 1.113 1. 005 Concentrates, percent 0 v 36 13. 36 Tails, percent Cu 197 .185 Reagents:

Lime .pounds per ton- 5. 42 5. 42 Cresylic acid .ldo-.-. 16 l6 Carbonyl bis diethyl d hiophosphate. do. .04 04 Diethyl phthalate .do. 01

Example III Test No 1 2 Heads, percent Cu 1. 206 Concentrates, percent Cu. 26 Tails, percent Cu 179 Reagents:

Lime pounds per tom. 5. 42 5. 42 Cresylic acld .do.-.- .16 l6 Aerofloat 208 .do.- 04 04 Diethyl phthalate. do 01 Example IV Test No 1 2 Heads, percent 011 l 2. 090 2.117 Concentrates, percent Cu 15. 60 l ,14. 68 Tails, percent Cu 293 242 Example V Test No 1 2 g 3 Heads, percent Cu 2.045 2.060 2.067 Concentrates, percent Cu 14.61 14. 61 14.10 Tails, percent 011...... 300 268 262 Reagents:

Sulphuric acid "pounds per ton 10.0 10.0 10.0 Oresylic acid -do. 44 44 44 Ethyl xanthogen ethyl formats pounds per tom. .20 .18 18 Dibutyl phthalate, ..do- 02 Example VI Test No 1 2 Heads, percent Cu .719 .724

Concentrates, percent Cu 18 36 20.19

Tails, percent Cu .204

Reagents:

Lime. pounds per tom. 8. 8.0

Pine oil do O9 09 Sodium xauthate do 10 Hexyl xanthogen ethy formate .do- .02225 Dlethyl phthalate .do 0075 Example VII Test No 1 2 Heads, percent Zn 4. 79 4. 86

Concentrates, percent Zn 29. 98 29. 9S

Tails, percent Zn 714 .408

Reagents:

Lime pounds per ton" 10.0 10. 0 Copper sulphate -do. 5 5 Pine oil .do.. .11 .11 Secondary butyl xanthogen ethyl formate pounds per ton. 05 U5 Diethyl phthalate "do.-. 01

Example VIII Test No 1 2 Heads, percent Zn 5.02 5.10

Concentrates, percent Zn 15.3 16. 9

Tails percent Zn l 27 22 Reagents:

Lime .pounds per ton 2. 2 2. 2 Copper sulphate do.. 1. 2 l. 2 Secondary butyl xanthogen ethyl formate pounds per ton 05 05 Aerofloat 25; .d O6 06 'Dihexyl phthalate do 01 Example IX Test No 1 2 Heads, percent Cu 790 790 Concentrates, percent Cu 19. 24 19.13

Tails, percent Cu .136 121 Reagents: 7

Lime pounds per ton 4. 0 4. 0 Pine oil do .11 .11 Secondary butyl xanthogen ethyl formate pounds per ton 02 02 Dihexyl phthalate .do 005 In the tests carried out to obtain the data set forth in the above examples, the froth produced in each of the tests in which a plasticizer was employed was resilient, flexible and workable, whereas in each of the tests carried out without the use of a plasticizer, a more brittle and. less stable froth was produced.

I claim:

1. The method of concentrating a sulphide mineral which comprises subjecting sulphide mineral-bearing material in the form of a pulp to a froth flotation operation in the presence of an anionic mineral collecting agent selected from the class consisting of alkyl xanthogen formates, alkali metal alkyl Xanthates and dialkyl dithiophosphates and a plasticizer selected from the group consisting of diethyl phthalate, dibutyl eral which comprises subjecting sulphide min- 6. The method of concentrating a sulphide mineralv which comprises subjecting sulphide mineral-bearing material in the form of a pulp to a froth flotation operation in the presence of secondary butyl xanthogen ethyl formate and diethyl phthalate.

'7. The method of concentrating a sulphide mineral which comprises subjecting sulphide mineral-bearing material in the form of a pulp to a froth flotation operation in the presence of secondary butyl xanthogen ethyl formate and dihexyl phthalate.

8. A flotation agent for use in a sulphide mineral concentrating process in which sulphide mineral-bearing material in the form of a pulp is subjected to a froth flotation operation in the presence of frothing and mineral collecting agents, said flotation agent being an intimate mixture comprising (1) a Water-insoluble mineral collecting agent'selected from the group consisting of alkyl xanthogen formates and (2) a plasticizer selected from the group consisting of dialkyl phthalates.

9. A flotation agent for use in a sulphide mineral concentrating process in which sulphide mineral-bearing material in the form of a pulp is subjected to a froth flotation operation in the presence of frothing and mineral collecting agents, said flotation agent being an intimate mixture comprising (1) a water-insoluble mineral collecting agent selected from the group consisting of alkyl xanthogen formates and (2) a .plasticizer selected from the group consisting of diethyl, dibutyl and dihexyl phthalates.

10. A flotation agent for use in a sulphide mineral concentrating process in which sulphide mineral-bearing material-in the form of a pulp is subjected to a froth flotation operation in the presence of frothing and mineral collecting agents, said flotation agent being an intimate mixture comprising (1) a water-insoluble mineral collecting agent selected from the group consisting of ethyl, butyl, amyl and hexyl xanthogen ethyl formates and (2) a plasticizer selected from the group consisting of dialkyl phthalates.

11. A flotation agent for use in a sulphide mineral concentrating process in which sulphide mineral-bearing material in the form of a pulp is subjected to a froth flotation operation in the presence of frothing and mineral collecting agents, said flotation agent being an intimate mixture comprising (1) a water-insoluble mineral collecting agent selected from the group consisting of ethyl, butyl, amyl and hexyl xanthogen ethyl formates and (2) a plasticizer selected from the group consisting of diethyl, dibutyl and dihexyl phthalates.

' (References on following page) References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Sulman et a1 June 28, 1910 Douglass Dec. 6, 1927 Christmann et a1. Dec. 22, 1936 Kirby Nov. 16, 1937 Heilmann May 16, 1944 Keck Apr. 17, 1945 Booth et a1 Q Oct. 29, 1946 10 FOREIGN PATENTS Number Country Date 19,644 Australia Oct. 10, 1934 5 OTHER REFERENCES Plasticizers for Adhesives etc., 1944 by Carbide and Carbon Chemicals Corporation, pages 2-5. (Copy in Scientific Library.)

Taggart, Handbook of Mineral Dressing,

10 1945, section 12, p. 42.

I-Iackhs Chemical Dictionary, Third edition,

printed 1946, p. 664. (Copy in Division 25.) 

1. THE METHOD OF CONCENTRATING A SULPHIDE MINERAL WHICH COMPRISES SUBJECTING SULPHIDE MINERAL-BEARING MATERIAL IN THE FORM OF A PULP TO A FROTH FLOTATION OPERATION IN THE PRESENCE OF AN ANIONIC MINERAL COLLECTING AGENT SELECTED FROM THE CLASS CONSISTING OF ALKYL XANTHOGEN FORMATES, ALKALI METAL ALKYL XANTHATES AND DIALKYL DITHIOPHOSPHATES AND A PLASTICIZER SELECTED FROM THE GROUP CONSISTING OF DIETHYL PHTHALATE, DIBUTYL PHTHALATE AND DIHEXYL PHTHALATE. 